From bc696ca05f5a8927329ec276a892341e006b00ba Mon Sep 17 00:00:00 2001 From: Borislav Petkov Date: Tue, 26 Jan 2016 22:12:05 +0100 Subject: x86/cpufeature: Replace the old static_cpu_has() with safe variant So the old one didn't work properly before alternatives had run. And it was supposed to provide an optimized JMP because the assumption was that the offset it is jumping to is within a signed byte and thus a two-byte JMP. So I did an x86_64 allyesconfig build and dumped all possible sites where static_cpu_has() was used. The optimization amounted to all in all 12(!) places where static_cpu_has() had generated a 2-byte JMP. Which has saved us a whopping 36 bytes! This clearly is not worth the trouble so we can remove it. The only place where the optimization might count - in __switch_to() - we will handle differently. But that's not subject of this patch. Signed-off-by: Borislav Petkov Cc: Andy Lutomirski Cc: Borislav Petkov Cc: Brian Gerst Cc: Denys Vlasenko Cc: H. Peter Anvin Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Thomas Gleixner Link: http://lkml.kernel.org/r/1453842730-28463-6-git-send-email-bp@alien8.de Signed-off-by: Ingo Molnar --- arch/x86/include/asm/fpu/internal.h | 14 +++++++------- 1 file changed, 7 insertions(+), 7 deletions(-) (limited to 'arch/x86/include/asm/fpu') diff --git a/arch/x86/include/asm/fpu/internal.h b/arch/x86/include/asm/fpu/internal.h index d01199def781..c2e46eb96b6d 100644 --- a/arch/x86/include/asm/fpu/internal.h +++ b/arch/x86/include/asm/fpu/internal.h @@ -59,22 +59,22 @@ extern u64 fpu__get_supported_xfeatures_mask(void); */ static __always_inline __pure bool use_eager_fpu(void) { - return static_cpu_has_safe(X86_FEATURE_EAGER_FPU); + return static_cpu_has(X86_FEATURE_EAGER_FPU); } static __always_inline __pure bool use_xsaveopt(void) { - return static_cpu_has_safe(X86_FEATURE_XSAVEOPT); + return static_cpu_has(X86_FEATURE_XSAVEOPT); } static __always_inline __pure bool use_xsave(void) { - return static_cpu_has_safe(X86_FEATURE_XSAVE); + return static_cpu_has(X86_FEATURE_XSAVE); } static __always_inline __pure bool use_fxsr(void) { - return static_cpu_has_safe(X86_FEATURE_FXSR); + return static_cpu_has(X86_FEATURE_FXSR); } /* @@ -301,7 +301,7 @@ static inline void copy_xregs_to_kernel_booting(struct xregs_state *xstate) WARN_ON(system_state != SYSTEM_BOOTING); - if (static_cpu_has_safe(X86_FEATURE_XSAVES)) + if (static_cpu_has(X86_FEATURE_XSAVES)) XSTATE_OP(XSAVES, xstate, lmask, hmask, err); else XSTATE_OP(XSAVE, xstate, lmask, hmask, err); @@ -323,7 +323,7 @@ static inline void copy_kernel_to_xregs_booting(struct xregs_state *xstate) WARN_ON(system_state != SYSTEM_BOOTING); - if (static_cpu_has_safe(X86_FEATURE_XSAVES)) + if (static_cpu_has(X86_FEATURE_XSAVES)) XSTATE_OP(XRSTORS, xstate, lmask, hmask, err); else XSTATE_OP(XRSTOR, xstate, lmask, hmask, err); @@ -461,7 +461,7 @@ static inline void copy_kernel_to_fpregs(union fpregs_state *fpstate) * pending. Clear the x87 state here by setting it to fixed values. * "m" is a random variable that should be in L1. */ - if (unlikely(static_cpu_has_bug_safe(X86_BUG_FXSAVE_LEAK))) { + if (unlikely(static_cpu_has_bug(X86_BUG_FXSAVE_LEAK))) { asm volatile( "fnclex\n\t" "emms\n\t" -- cgit v1.2.1